1. Field of the Invention
The present invention relates to a three-dimensional information reproducing apparatus which inputs three-dimensional information and can reproduce a three-dimensional image without the need of special spectacles.
2. Description of the Related Art
Up to this time, there is known a three-dimensional information reproducing apparatus of the integral photographic type which inputs the state of a light beam traveling through a three-dimensional space, such as the traveling direction, and reproduces the traveling direction of a light beam. The three-dimensional information apparatus of the integral photographic type combines a pinhole array and photographic technique and has been applied as stereoscopic photography.
There is known a three-dimensional information reproducing apparatus using an image display device capable of displaying a dynamic picture image such as a liquid crystal panel instead of the photosensitive film in photography. This three-dimensional information apparatus is comprised of a liquid crystal panel 1 for displaying an image, a pinhole array panel 2 arranged in front of the liquid crystal panel 1, a diffusion plate 3 arranged in rear of the liquid crystal panel 1 for diffusing light, and a light source 4 for irradiating the diffusion plate 3 with light, as shown in FIG. 1. As shown in FIG. 2, a plurality of pinholes 5 are bored in the pinhole array panel 2 in the vertical and horizontal directions at pitch-P intervals. A plurality of pixels are spatially determined and two-dimensionally arranged on the liquid crystal panel 1, corresponding to the respective pinholes 5. To the liquid crystal panel 1 and the pinhole array panel 2 there is connected a synchronous control circuit 8.
Next, the principles of the reproduction of a three-dimensional image in the conventional three-dimensional information reproducing apparatus shown in FIG. 1 will be described with FIG. 3. In the FIG. 3, a pixel block 6 of 4.times.4 (=16) pixels is assigned to each of the pinholes 5a, 5b, 5c . . . on the pinhole array panel 2. Part of light radiated from some pixel block 6 on the liquid crystal panel 1 travels in a direction that is determined by the spatial position of the pinhole 5 corresponding to that pixel block 6. Light beams in various directions are reproduced by a combination of the pixel block 6 and the position of the pinhole 5, so a spatial image is formed in an observation space by a group of light beams emitted from a plurality of pinholes 5. In the example of FIG. 3, light beams radiated from an object S in plural directions have been reproduced.
Light from the object S is originally scattered in all directions, and the pinhole 5 has a function of sampling the light scattering from the object 5 in all directions. Therefore, if the number of the pinholes 5 are increased, the reproducibility of light beams will be increased. It is needless to say that a continuous body to be photographed can be reproduced by arranging a plurality of the pinholes 5.
If an observer 100 perceives a light beam emitted from the pinhole 5 by his or her eyes, three-dimensional information of the object S will be recognized. That is, the object S is recognized as a three-dimensional image. In the three-dimensional information reproducing apparatus of the type in which a light-beam state such as this is reproduced, special spectacles are unnecessary, the observation position is not limited extremely like a so-called lenticular method, and a plurality of people can observe a reproduced picture image at the same time. There is the advantage that if a visual point is moved, then an image to be observed will be changed according to the movement of the visual point. The factor that recognizes a reproduced picture image as a three-dimensional image is not only binocular parallax, but also the factor is that the distance feeling of a reproduced picture image, i.e., three-dimensional feeling is recognized by the focussing function of eyes. Therefore, there is a little fatigue feeling at the time of observation, a more natural three-dimensional image can be observed, and three-dimensional information can be recognized even by one eye.
A three-dimensional information inputting method that is displayed in the three-dimensional information apparatus shown in FIGS. 1 and 3 will be described making reference to FIG. 4.
A picture image of one picture screen that is displayed is not photographed at a time, but small portions of a picture image are photographed in order. A video camera lens 7 is parallel moved up, down, right and left at same intervals as the pinhole pitch P of the pinhole array panel 2 shown in FIG. 3, and photographing is performed at positions corresponding to the respective pinholes 5. The intersecting points of a line group in FIG. 4 correspond to the positions of the pinholes 5 in FIG. 3, respectively, and a picture image is photographed at a position that the center of the video camera lens 7 becomes equal to the intersecting point of the above-described line group, so picture images are photographed by the number of pinholes.
In FIG. 3 the pixel block 6 of 4.times.4 (=16) pixels on the liquid crystal panel 1 is assigned to one pinhole 5 on the panel 2. Therefore, for a picture image that is obtained with the method shown in FIG. 4 by a camera located at the pinhole position, only 16 pixels of 4.times.4 become necessary at the central portion of the camera, as shown in FIG. 5. Note that a circle shown by a dotted line represents the range of a picture image that is photographed by the above-described lens 7.
If 16 pixels photographed and extracted are numbered from 1 to 16, as shown in FIG. 5, they need to be rearranged in displaying them on the liquid crystal panel 1, as shown in FIG. 6. This is because an image in which the depth side and this side are inverted in the depth direction will be reproduced if the pixels shown in FIG. 5 are displayed as they are. The right image can be reproduced by rearranging each pixel, as shown in FIG. 6. This rearranging process must be performed for the photographing position of the video camera, i.e., the position corresponding to the pinhole. The pixel 6 on the liquid crystal panel 1 consists of three subpixels 8 (R (red), G (green), and B (blue) subpixels) arranged in the horizontal direction, as shown in FIG. 7B. In the above-described three-dimensional information reproducing apparatus, the emission direction of a reproduced light is determined by the pinhole 5 and the relative position of the pixel 6 corresponding to the pinhole 5, so the emission direction of the reproduced light will be different if the position of the pixel is different. The reproduced light beams emitted from the respective pixels 6 pass through the pinholes 5 and travel in different directions.
As described above, in the three-dimensional information reproducing apparatus of this type, the number of pinholes is preferable to be increased. In order to realize this, a case where the pinhole array panel in FIG. 2 is constituted by an optical shutter such as a liquid crystal panel is disclosed in Japanese Patent Laid-open Publication No. 5-191838. When the pinhole array panel is constituted by a plastic material, etc, the position of the pinhole is fixed, but when the pinhole array panel is constituted by an optical shutter such as a liquid crystal panel, it is possible to freely change the position of the pinhole. Therefore, time division display of a three-dimensional image is performed by synchronizing the position of a pinhole and a display image corresponding to that and changing them at high speeds, so it is possible to enhance practical resolution.
The feature of the case where the pinhole array is constituted by an optical shutter such as a liquid crystal panel is in that the position of the pinhole array is varied with time, but in this embodiment a case where during one cycle the position of the pinhole changed to four kinds of two horizontal positions.times.two vertical positions will be described in accordance with FIGS. 8A to 8D. A dotted line in the figures is written so that the pinhole positions can easily be compared, and does not have special meanings. If it is assumed that the pinhole 5 is located in the upper left-hand corner of a lattice formed by the dotted lines, as shown in FIG. 8A, the position of the pinhole 5 will be changed at the next time so that the pinhole 5 is located in the upper right-hand corner of the lattice formed by the dotted lines, as shown in FIG. 8B. At this time, the position of the pinhole 5 shown in FIG. 8B is located at the horizontal central position between two adjacent pinholes 5 shown in FIG. 8A. At the next time, the position of the pinhole 5 is changed so that the pinhole 5 is located in the lower right-hand corner of the lattice formed by the dotted lines, as shown in FIG. 8C. At this time, the position of the pinhole 5 shown in FIG. 8C is located at the vertical central position between two adjacent pinholes 5 shown in FIG. 8A. At the next time, the position of the pinhole 5 is changed so that the pinhole 5 is located in the lower right-hand corner of the lattice formed by the dotted lines, as shown in FIG. 8D. The states from FIG. 8A to FIG. 8D are repeated in this way, and time division display of a three-dimensional image is so performed as to correspond to the respective pinhole positions, by switching a picture image that will be displayed on the liquid crystal panel in synchronization with the respective pinhole positions.
Next, the reproduction state of a light beam at this time will be described with FIGS. 9A and 9B.
The display pixels on the liquid crystal panel 1 are numbered from 1 to 14 in the horizontal direction. As shown in FIG. 9A, a pinhole A corresponds to the pixels 4 to 7 and a pinhole B corresponds to the pixels 8 to 11. If the pinhole position is changed as shown in FIG. 9B, the state of reproduction of light beams will also change according to the change of the pinhole position, the pinhole A will correspond to the display pixels 2 to 5, and the pinhole B will correspond to the display pixels 8 to 9.
A conventional three-dimensional information reproduction apparatus is constructed as described above, and consequently, in the case of a three-dimensional information reproducing apparatus constructed by the liquid crystal panel 1 in which pixels 6 of red, green, and blue are arranged in different positions on a plane, the pinhole array panel 2, etc., the emission direction of a reproduced light beam is determined by the pinhole and the relative position of the pixel of the liquid crystal panel corresponding to the pinhole, so the emission direction of the reproduced light beam is different for different colors and color dislocation will occur in the reproduced image, by a difference in the positions of the color filters arranged. Since the reproduced light beams emitted from each pixel travel through the pinholes in different directions, an observer observing these light beams cannot see a three-dimensional image of the right color.
The pinhole array panel and a slit array panel transmit only part of light emitted from the liquid crystal panel and interrupt most of the remaining light, so the efficiency of utilization of light is extremely low and a picture image that will be reproduced becomes dark. Particularly when the pinhole array is used, the darkness of a picture image that will be reproduced is remarkable and the observation of a reproduced picture image is difficult under a room illumination light.
The resolution of a reproduced picture image depends upon the number of pinholes and the number of pixels of a liquid crystal panel corresponding to one pinhole. Since the total number of pixels of the liquid crystal panel is limited, there is the relationship that if one of the number of pinholes and the number of pixels of the liquid crystal panel corresponding to one pinhole is increased, the other will be decreased, so it is difficult to obtain a reproduced image which is high in resolution. In a conventional apparatus in which the pinhole array was constituted not by a plastic material but by an optical shutter such as a liquid crystal panel, a reproduced image that is high in resolution can be obtained by moving the position of the optical shutter with time division, but since the emission direction of a reproduced light beam is determined by the optical shutter and the relative position of the pixel of the liquid crystal panel corresponding to the optical shutter, the emission direction of the reproduced light beam is different by a different in colors and color dislocation will occur in the reproduced image, by a difference in the positions of the color filters arranged. Further, the optical shutter transmits only part of light emitted from a liquid crystal panel and interrupts most of the remaining light, so the efficiency of utilization of light is extremely low and only a dark picture image can be reproduced. These problems are a great obstacle to observation, and in an extreme case, binocular vision itself becomes impossible.
Since the display pixel and the pinhole have a finite size, the emitted light from the pinhole spreads out and a reproduced image becomes obscure. The pinhole is ideally an infinitely small bore, but in a case where the pinhole is constituted by an optical shutter such as a liquid crystal panel, the size of the pinhole cannot be reduced to less than the pixel size of the liquid crystal panel. Therefore, the light emitted from the pinhole, as shown in FIG. 10, spreads out in proportion to the distance from the pinhole, so a reproduced image becomes dim.
Since the pinhole has a finite size, the cross talk of reproduced light will occur. As shown in FIG. 10, the light emitted from the pinhole 5 spreads out in proportion to the distance from the pinhole, and consequently, the emission light from the pixel 1 and the emission light from the pixel 2 are mixed in the portion indicated by oblique lines in the figure, so a recorded light beam cannot be reproduced.
The foregoing is put together and shown in Table 1. Note that the kind of the three-dimensional information reproducing apparatus is limited to a method of reproducing the state of a light beam.
TABLE 1 ______________________________________ Kind of three- Pinhole Multiple Plural- Single- dimensional array lens in pinhole slit reproducing the form time time apparatus of a division division (using a fly's movement movement dynamic picture eye display panel) Color Occur Occur Occur Occur dislocation occurs due to the arrangement of R, G, and B Image Very Light Very Dark becomes dark dark dark due to the interruption of a light beam Degree of Large Large Rela- Rela- deterioration tively tively in resolution small small (as compared with two- dimensional display) Direction of Horizon- Horizon- Horizon- Only parallax tality tality tality horizon- and and and tality verti- verti- verti- cality cality cality ______________________________________